Superficial temporal artery–middle cerebral artery bypass for ischemic atherosclerotic middle cerebral artery disease

Extracranial-Intracranial Cerebral Revascularization for Atherosclerotic Vessel Occlusion: An Updated Systematic Review of the Literature

BACKGROUND

Atherosclerotic steno-occlusive cerebrovascular disease includes extracranial carotid occlusive and intracranial atherosclerotic disease. Despite the negative findings in Carotid Occlusion Surgery Study (COSS), many large centers continue to report favorable results for revascularization surgery in select groups of patients. The aim of our study was to perform an updated systematic review to investigate the role of revascularization surgery for atherosclerotic steno-occlusive patients in the modern era.

METHODS

Five independent reviewers performed Preferred Reporting Items for Systematic Reviews and Meta-Analyses-guided literature searches in October 2022 to identify articles reporting clinical outcomes in adult patients undergoing bypass for atherosclerotic steno-occlusive disease. Primary endpoints used were perioperative and long-term ischemic strokes, intracerebral hemorrhage, bypass patency, and favorable clinical outcomes. Study quality was evaluated with Newcastle-Ottawa, JADAD, and the Oxford Center for Evidence-Based Medicine scales.

RESULTS

A total of 6709 articles were identified in the initial search. Of these articles, 50 met the inclusion criteria and were included in the systematic review. A notable increase in the proportion of articles published over the past 10 years was observed. There were 6046 total patients with 4447 bypasses performed over the period from 1978 to 2022. The average length of follow-up was 2.75 ± 2.71 years. The average Newcastle-Ottawa was 6.23 out of 9 stars. There was a significant difference in perioperative stroke (odds ratio [OR], 0.65 [0.48-0.87]; P = 0.004), long-term ischemia (OR, 0.32 [0.23-0.44]; P < 0.0001), overall ischemia (OR, 0.36 [0.28-0.44]; P < 0.0001), and favorable outcomes (OR, 3.63 [2.84-4.64]; P < 0.0001) when comparing pre-COSS to post-COSS time frames in favor of post-COSS.

CONCLUSIONS

Based on a systematic review of 50 articles, the existing literature indicates that long-term stroke rates and favorable outcomes for surgical revascularization for steno-occlusive disease have improved over time and are lower than previously reported. Improved patient selection, perioperative care, and surgical techniques may contribute to improved outcomes.

Risk of subsequent stroke, with or without extracranial-intracranial bypass surgery: a nationwide, retrospective, population-based study

OBJECTIVE

Although no benefits of extracranial-intracranial (EC-IC) bypass surgery in preventing secondary stroke have been identified previously, the outcomes of initial symptomatic ischemic stroke and stenosis and/or occlusion among the Asian population in patients with or without bypass intervention have yet to be discussed. The authors aimed to evaluate the subsequent risk of secondary vascular disease and cardiac events in patients with and without a history of this intervention.

METHODS

This retrospective nationwide population-based Taiwanese registry study included 205,991 patients with initial symptomatic ischemic stroke and stenosis and/or occlusion, with imaging data obtained between 2001 and 2010. Patients who underwent EC-IC bypass (bypass group) were compared with those who had not undergone EC-IC bypass, carotid artery stenting, or carotid artery endarterectomy (nonbypass group). Patients with any previous diagnosis of ischemic or hemorrhagic stroke, moyamoya disease, cancer, or trauma were all excluded.

RESULTS

The risk of subsequent ischemic stroke events decreased by 41% in the bypass group (adjusted hazard ratio [HR] 0.59, 95% CI 0.46-0.76, p < 0.001) compared with the nonbypass group. The risk of subsequent hemorrhagic stroke events increased in the bypass group (adjusted HR 2.47, 95% CI 1.67-3.64, p < 0.001) compared with the nonbypass group.

CONCLUSIONS

Bypass surgery does play an important role in revascularization of the ischemic brain, while also increasing the risk of hemorrhage in the early postoperative period. This study highlights the fact that the high risk of bypass surgery obscures the true benefit of revascularization of the ischemic brain and also emphasizes the importance of developing improved surgical technique to treat these high-risk patients.

Superficial temporal artery-middle cerebral artery bypass for the treatment of complex middle cerebral artery aneurysms

Objectives:

Direct microsurgical clipping for complex middle cerebral artery (MCA) aneurysms may require a long ischemic time. Sacrifice of the parent artery with trapping or endovascular coiling also may lead to ischemic stroke. We described our institutional experience with the treatment of complex MCA aneurysms using extracranial-intracranial (EC-IC) (superficial temporal artery [STA]-MCA) bypass.

Materials and Methods:

We retrospectively reviewed patients who had treatment of IC aneurysms with the assistance of STA-MCA bypass from July 2002 to December 2016. Six patients with complex MCA aneurysms were identified, and we reviewed their clinical characteristics.

Results:

There were three men and three women with age ranging from 27 to 59 (mean 49) years old. Image studies showed subarachnoid hemorrhage in three cases. All patients underwent STA-MCA anastomosis, and the follow-up period ranged from 2 to 116 months (mean 51.5 months). Two of the six MCA aneurysms were fusiform, two aneurysms had bizarre configurations, one was a dissecting saccular aneurysm, and one had a blister configuration. Three patients received direct vessel trapping, two patients received aneurysm clipping, and one received aneurysm coiling. The postoperative bypass patency rate was 100%. The modified Rankin scale showed good outcomes in the six patients.

Conclusions:

EC-IC bypass plays an important role as a salvage procedure in the treatment of complex MCA aneurysms which have a fusiform, bizarre, or blister configuration.

Extracranial-intracranial bypass for ischemic cerebrovascular disease: what have we learned from the Carotid Occlusion Surgery Study?

Extracranial-intracranial (EC-IC) arterial bypass has been used in the treatment of various neurosurgical pathologies including skull base tumors requiring sacrifice of a large intracranial artery; complex intracranial aneurysms requiring trapping; and distal revascularization, moyamoya disease, and symptomatic cerebrovascular stenoocclusive disease. The latter indication has been the subject of intense investigations in several large randomized controlled trials, most recently the Carotid Occlusion Surgery Study (COSS). In the present literature review and synthesis, the authors examine the current evidence available for EC-IC arterial bypass for the treatment of ischemic cerebrovascular disease including both extracranial carotid artery occlusive disease and intracranial atherosclerotic disease. They focus particular attention on EC-IC arterial bypass for the treatment of symptomatic hemodynamic cerebral ischemia and how lessons learned from the COSS might guide future investigations into the treatment of this disease.

Watertight dural closure constructed with DuraSeal TM for bypass surgery

Superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis is a common procedure for the treatment of cerebral ischemia and is useful for cerebral aneurysms and tumors. The STA has to pass through the dura and the dura cannot be sutured tightly around the STA to prevent vessel narrowing, so subcutaneous cerebrospinal fluid (CSF) collection is common. This study analyzed the feasibility of using a synthetic dural sealant in the STA-MCA anastomosis to establish watertight closure. Twenty-four patients underwent STA-MCA anastomosis for cerebral ischemia or cerebral aneurysm. After creation of a standard STA-MCA anastomosis, the dura was reapproximated closely, leaving a small defect around the STA. Then, DuraSeal(TM) was sprayed over the dural defect, and a negative-pressure drain was positioned before closing the skin. Only two patients developed subcutaneous CSF collection, which was managed conservatively. The patency of the anastomosis was proven by magnetic resonance angiography in all cases, and no ischemic complication suggesting chemical spasm of the STA due to the sealant occurred. With DuraSeal(TM), watertight dural closure can be obtained easily and safely in bypass surgery.

Symptomatic intracranial arterial disease: incidence, natural history, diagnosis, and management

Symptomatic intracranial arterial disease is associated with a high rate of recurrent ischemic events. The management of this condition is controversial, with some advocating medical therapy as a sole means of treatment and others recommending endovascular therapy in addition to best medical management. In rare cases, surgical intervention is considered. A thorough review of the available literature was performed, and treatment recommendations based on these data are provided.

MR angiography and imaging for the evaluation of middle cerebral artery atherosclerotic disease

Intracranial atherosclerotic disease may constitute the most common cause of ischemic stroke worldwide; yet, in the developed world, imaging research has largely focused on extracranial atherosclerosis. Many studies in populations of Asian, African, and Hispanic descent demonstrate the preponderance of intracranial stenosis compared with carotid stenosis. This review examines the clinical presentations of MCA atherosclerosis and stenosis and the use of noninvasive MR imaging in the assessment of intracranial vasculature. MRA is a well-validated technique that offers great advantage over traditional angiography. Advances in high-resolution MR imaging of MCA stenosis have the potential to yield excellent visualization of plaque. Future developments in high-resolution MR imaging to depict intracranial atherosclerosis are explored in this review; these advances will guide endovascular therapy and the comparison of novel interventions.